From: Milton Miller <miltonm@bga•com>
To: David Gibson <david@gibson•dropbear.id.au>
Cc: ppcdev <linuxppc-dev@ozlabs•org>
Subject: Re: [PATCH 8/15] bootwrapper: convert flatdevtree to version 16
Date: Thu, 27 Sep 2007 10:44:27 -0500 [thread overview]
Message-ID: <41180fced14196db80f261d2ac1909e0@bga.com> (raw)
In-Reply-To: <20070927024535.GC14030@localhost.localdomain>
On Sep 26, 2007, at 9:45 PM, David Gibson wrote:
> On Wed, Sep 26, 2007 at 11:19:47AM -0500, Milton Miller wrote:
>> On Sep 24, 2007, at 10:46 PM, David Gibson wrote:
>>> On Mon, Sep 24, 2007 at 01:54:32AM -0500, Milton Miller wrote:
>>>> On Sep 23, 2007, at 10:36 PM, David Gibson wrote:
>>>>> On Fri, Sep 21, 2007 at 06:05:06PM -0500, Milton Miller wrote:
>>> [snip]
>>>>>> +#define MIN_VERSION 2
>>>>>> +#define OUT_VERSION 16z
>>>> Actually the v1 trees has
>>>> some other differences such as initrd addresses were kernel linear
>>>> not
>>>> real, cpus were assigned logical numbers ... so while the structure
>>>> didn't change except for the header field, the contents did.
>>>
>>> !? what's your source for this. v2 and v3 were absolutely supposed
>>> to
>>> be backwards compatible with v1 which would not be the case with
>>> silent semantic changes such as this.
>>
>> What's your souce for saying the were supposed to be backwards
>> compatable? That dtc fills out the struct header so?
>
> Sitting next to BenH and knowing he always intended them to be so.
>
>> My source is my involvment when v2 was defined (they were discovered
>> while writing my device tree generation code):
>>
>> The actual binary structure is compatable, just not the contents of
>> the
>> properties nor how any slave cpus wait (for some trees it doesn't
>> matter).
>>
>> http://git.kernel.org/?p=linux/kernel/git/horms/kexec-tools-
>> testing.git;a=blob;f=kexec/arch/ppc64/fs2dt.c;
>> hb=b84b87747a16f0afbef6f6802bb794a94f4961d9
>
> An old version of fs2dt is hardly definitive. It could just be Plain
> Wrong, nothing to do with the dt version.
Sorry, copy and paste error. I was tring to point out this changelog
in 2.6.10:
http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;
a=commitdiff;h=e1b47549d1588ccea1fa5726eb430aae4e80f8ed
>
>> And some more changes just before that:
>>
>> http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;
>> a=history;f=arch/ppc64/kernel/prom_init.c;
>> h=e570799a84cc5328e9f0fd44592cb0b828d8c13a;
>> hb=4ae24c4e8a8f68950a7774ca1cdfe69bfe4e2ffc
>
> I don't know what bit you're referring to in that batch of commits.
The following properties changed semantics and no heuristics are
employed to check for the old vs new:
(1) tces changed from virtual to real
(2) cpus spin on physical (hw id) not logical (0-n)
Other changes in that series
(3) 0->klimit is not a memreserve in the tree (we now allow overlapping
reserves, but not at the time)
(4) rtas properties are in a different location (but both could exist)
>
>> So its mostly when the kernel generated and required v1 trees, it was
>> ppc64 only and had these other content and handoff semantics. If it
>> were to get a v1 tree, it only copes for the boot cpu determination
>> I'm not aware of any code other than the kernel that would actually
>> generate a v1 tree (other than dtc, which always supporteed v2, and
>> doesn't care about these differences).
So trying to boot 2.6.9 (2004-10-18 cutoff) kernel from a tree for
2.6.10 would fail, and vice versa. But a 2.6.10 kernel can boot a v1
tree with properties, memreserves, and cpu ids that it expects, getting
the boot-cpuid from the extra property in the tree.
Is that compatible? If you only are talking about parsing the tree it
is.
milton
next prev parent reply other threads:[~2007-09-27 15:44 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-21 23:02 [PATCH 0/15] bootwrapper: kexec and external payloads Milton Miller
2007-09-21 23:03 ` [PATCH 1/15] boot: find initrd location from device-tree Milton Miller
2007-09-24 2:58 ` David Gibson
2007-09-24 5:50 ` Rob Landley
2007-09-24 8:02 ` Milton Miller
2007-09-25 3:27 ` David Gibson
2007-09-26 5:49 ` Milton Miller
2007-09-21 23:03 ` [PATCH 2/15] boot: record header bytes in gunzip_start Milton Miller
2007-09-24 2:59 ` David Gibson
2007-09-21 23:03 ` [PATCH 3/15] boot: simplfy gunzip_finish Milton Miller
2007-09-21 23:03 ` [PATCH 4/15] bootwrapper: smp support code Milton Miller
2007-09-21 23:04 ` [PATCH 5/15] bootwrapper: occuppied memory ranges Milton Miller
2007-09-24 3:09 ` David Gibson
2007-09-24 9:33 ` Milton Miller
2007-09-21 23:04 ` [PATCH 6/15] bootwrapper: help for 64 bit cpus Milton Miller
2007-09-24 3:14 ` David Gibson
2007-09-21 23:04 ` [PATCH 7/15] bootwrapper: Add kexec callable zImage wrapper Milton Miller
2007-09-24 3:23 ` David Gibson
2007-09-21 23:05 ` [PATCH 8/15] bootwrapper: convert flatdevtree to version 16 Milton Miller
2007-09-24 3:36 ` David Gibson
2007-09-24 6:54 ` Milton Miller
2007-09-25 3:46 ` David Gibson
2007-09-26 16:19 ` Milton Miller
2007-09-27 2:45 ` David Gibson
2007-09-27 15:44 ` Milton Miller [this message]
2007-09-28 2:40 ` David Gibson
2007-09-28 15:16 ` Milton Miller
2007-10-03 5:29 ` David Gibson
2007-09-21 23:05 ` [PATCH 9/15] bootwrapper: rtas support Milton Miller
2007-09-24 3:46 ` David Gibson
2007-09-21 23:05 ` [PATCH 10/15] bootwrapper: add cpio file extraction library Milton Miller
2007-09-21 23:06 ` [PATCH 11/15] bootwrapper: allow vmlinuz to be an external payload Milton Miller
2007-09-21 23:06 ` [PATCH 12/15] bootwrapper: kexec extract vmlinux from initramfs Milton Miller
2007-09-21 23:06 ` [PATCH 13/15] bootwrapper: attach an empty vmlinux Milton Miller
2007-09-24 4:03 ` David Gibson
2007-09-21 23:08 ` [PATCH 14/15] boot: add a hook to start cpus Milton Miller
2007-09-21 23:08 ` [PATCH 15/15] bootwrapper: recheck for command line after fixups Milton Miller
2007-09-21 23:08 ` [PATCH 1/2] qemu platform, v2 Milton Miller
2007-09-22 9:55 ` Christoph Hellwig
2007-09-22 19:16 ` Rob Landley
2007-09-23 4:27 ` Paul Mackerras
2007-09-23 22:01 ` Rob Landley
2007-09-28 16:53 ` Segher Boessenkool
2007-09-28 20:14 ` Rob Landley
2007-10-01 5:33 ` David Gibson
2007-10-17 20:28 ` Grant Likely
2007-10-17 23:09 ` Rob Landley
2007-10-18 9:59 ` Matt Sealey
2007-10-18 17:19 ` Milton Miller
2007-10-18 17:29 ` Grant Likely
2007-10-19 6:28 ` Rob Landley
2007-09-24 4:00 ` David Gibson
2007-09-24 7:46 ` Christoph Hellwig
2007-09-24 9:48 ` Milton Miller
2007-09-21 23:08 ` [PATCH 2/2] qemu platform rom, v2 Milton Miller
-- strict thread matches above, loose matches on Subject: below --
2007-07-10 22:07 [PATCH 0/15] bootwrapper: support for kexec to zImage Milton Miller
2007-07-10 22:10 ` [PATCH 8/15] bootwrapper: convert flatdevtree to version 16 Milton Miller
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